Flow stop insert apparatus and methods

ABSTRACT

An embodiment is directed to pressure plate for attachment to an infusion pump, where the pressure plate includes a tubing support surface at least partially surrounded by a raised perimeter support. The pressure plate includes a plurality of guide structures extending from the raised perimeter support that define a passageway for an infusion pump tube. Additionally an attachable flow stop assembly is included that includes an attachable occlusion arch and an attachable flow stop arm. The attachable occlusion arch includes a plurality of tab structures that couple to the raised perimeter support. The occlusion arch further includes an aperture configured to surround an infusion pump tube threaded therethrough. The attachable flow stop arm is operatively coupled to the raised perimeter support adjacent the attachable occlusion arch in a spring-biased fashion such that the aperture in the occlusion arch may be selectively occluded by the flow stop arm.

RELATED APPLICATION

This application is a division of application Ser. No. 13/443,390 filedApr. 10, 2012, which is hereby fully incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to features for governing the flow offluid in medical infusion pumps. More specifically, this inventionrelates to a flow stop insert for an infusion pump having an improveddesign for operation and manufacture.

BACKGROUND OF THE INVENTION

Infusion pumps, drug pumps and medication delivery devices arewell-known and widely used throughout the world today. Intravenousinfusion pumps were developed decades ago to pump fluid medicants ornutrients through a tube set to a patient in connection with treatmentof a medical condition. Infusion pumps include peristaltic pumps, rollerpumps, or expulsor pumps, for example. Various pumps include a reusablecontrol module that is detachably coupled to a pressure plate on the topof a disposable or reusable fluid reservoir cassette. Fluid is pumpedfrom the cassette by the reusable control module when the cassette iscoupled to the control module. Alternatively, other variations ofinfusion pumps include a reusable pump control module and pressure platecassette as part of an administration set that is used in conjunctionwith a remote IV bag or fluid reservoir which is separate from the pumpcontrol.

Infusion pumps operate by governing the movement of fluid through adelivery tube by selectively occluding portions of the tube bydepressing a valve or mechanism against the tube. For example, in somepumps the mechanism of a pump selectively engages the tube against thepressure plate in a peristaltic fashion to force fluid through the tube.

In the past, one potentially problematic situation has been identifiedwhich is referred to as “free-flow”. Free flow occurs in infusion pumpswhen fluid flows freely from the source of fluid through the tube intothe patient. Medical personnel and pump operators try to avoid theoccurrence of free-flow when administering fluids to patients.

Free-flow may cause serious harm to a patient due to overmedication.Accordingly, designs and devices have been developed to prevent freeflow in infusion pumps. Although many of the free-flow preventiondesigns are somewhat effective, many designs suffer from arrangementsthat are difficult to manufacture or assemble. For example, many currentpressure plate arrangements for delivery tube placement contain featureswhich pose hard to assemble designs. Further, the components andoperation of past pressure plate designs are believed to be less thanoptimal and leave considerable room for improvement.

Therefore, improved methods and apparatus for selectively restrictingfluid flow of an infusion pump are desired, including improvements tothe pressure plate.

SUMMARY OF THE INVENTION

The present invention overcomes the problems of the prior art byproviding an improved device for governing fluid flow in an infusionpump. In general, fluid flow is governed through use of an attachableflow stop assembly or free flow protection device which occludes fluidflowing through an infusion pump tube, and related methods. In variousembodiments, fluid flow may be restricted at the pressure plate of areservoir cassette of an infusion pump.

One embodiment of the invention is directed to a pressure plate forattachment to an infusion pump. Specifically, the pressure plateincludes a tubing support surface at least partially surrounded by araised perimeter support comprising a raised rail and a plurality ofraised supporting structures. The pressure plate also includes aplurality of guide structures extending from the raised perimetersupport that define a passageway for an infusion pump tube.Additionally, in this embodiment an attachable flow stop assembly isincluded on the pressure plate. The attachable flow stop assemblyincludes an attachable occlusion arch and an attachable flow stop arm.The attachable occlusion arch includes a plurality of tab structuresthat attachably couple to the raised perimeter support. The occlusionarch further includes an aperture configured to surround an infusionpump tube threaded therethrough. The attachable flow stop arm isoperatively coupled to the raised perimeter support adjacent theattachable occlusion arch in a spring-biased fashion such that theaperture in the occlusion arch may be selectively occluded by the flowstop arm.

Another embodiment of the present invention is directed to a cassettereservoir attachment of an infusion pump. The cassette reservoirattachment includes a reservoir housing for enclosing a quantity offluid, an infusion tube to supply the fluid from the reservoir housingand a pressure plate. The pressure plate includes a tubing supportsurface for supporting a section of the infusion tube extending from thereservoir housing as well as a plurality of retention and guide featuresformed in the tubing support surface. The cassette reservoir attachmentalso includes a free flow protection device that prevents free-flow offluid in the tube. The free flow protection device includes anattachable occlusion arch with snaps, that attach to retention and guidefeatures, and an attachable flow stop arm, operatively coupled to theretention and guide features, for movement adjacent the attachableocclusion arch to selectively occlude an infusion tube passing throughthe occlusion arch.

Another embodiment of the invention is directed to an attachable flowstop assembly for use in occluding a tube of an infusion pump. Theattachable flow stop assembly includes an attachable occlusion arch andan attachable flow stop arm. More specifically, the attachable occlusionarch includes tab structures to attachably couple to a pressure plate ofan infusion pump and the occlusion arch defines a passageway to at leastpartially surround a length of an infusion pump tube. Further, theattachable flow stop arm is operatively coupled to the pressure platefor movement adjacent the attachable occlusion arch in a spring-biasedfashion to selectively occlude the passageway defined by the occlusionarch.

According to an embodiment of the present invention, a method ofassembling a cassette for an infusion pump is provided. The methodincludes providing an infusion pump reservoir cassette containing aninterior reservoir bag and a top surface comprising a pressure plate.The method also includes extending an infusion tubing, coupled to thereservoir bag at a location proximate an opening in the pressure plate,through an aperture in an attachable flow stop assembly and across thesurface of the pressure plate. In this embodiment, the attachable flowstop includes an attachable occlusion arch defining the aperture andhaving legs with one or more tab members for providing coupledengagement and an attachable flow stop arm. The method also includessecuring the tab members to features in the pressure plate.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of an assembled infusion pump arrangement,according to an embodiment of the invention.

FIG. 2 is an exploded, fragmentary view of the pump assembly, accordingto an embodiment of the invention.

FIG. 3 is an exploded view of flow stop assembly components, accordingto an embodiment of the invention.

FIG. 4 depicts the flow stop assembly components of FIG. 3 coupledtogether in an assembled fashion, according to an embodiment of theinvention.

FIG. 5A is a perspective view of an embodiment of flow stop assemblycomponents coupled together in an assembled fashion, according to anembodiment of the invention.

FIG. 5B is a perspective view of a pressure plate including the flowstop assembly components of FIG. 5A, according to an embodiment of theinvention.

FIG. 6 is a cross-sectional view of a pressure plate recess forplacement of a flow stop insert, according to an embodiment of theinvention.

FIG. 7A is a perspective view of an exemplary pressure plate of aninfusion pump assembly of the prior art.

FIG. 7B is a top view of the free-flow control portions of an exemplarypressure plate of the prior art.

FIG. 8 is an exploded view of an alternate embodiment of a flow stopassembly, according to an embodiment of the invention.

FIG. 9 is an exploded view of an alternate embodiment of a flow stoparch, according to an embodiment of the invention.

FIG. 10 is an exploded view of an alternate embodiment of a flow stoparch, according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention may be embodied in other specific forms without departingfrom the essential attributes thereof, therefore, the illustratedembodiments should be considered in all respects as illustrative and notrestrictive.

In various embodiments of this invention an apparatus and method aredisclosed for an improved flow stop device for infusion pumps. FIG. 1generally depicts an example of an infusion pump 10 which includes acontrol module 12 and a cassette 14 in coupled arrangement.Specifically, the cassette 14 includes a container portion 16 whichdefines a space for housing and generally enclosing a bag or reservoirof medication and a pressure plate 18 extending across the upper surfaceof the cassette. Control module 12 and cassette 14 may be of variousdesigns, sizes and shapes that are not limited to the sizes or types ofpumps or cassettes as depicted in the figures. Infusion pumps mayinclude peristaltic pumps, roller pumps, expulsor pumps, or other pumps.Cassettes are not limited to the large cassettes depicted in FIG. 1A andmay be of any size and shape. Cassettes may be disposable or reuseableand may be sealed or able to be readily opened.

Although the flow stop device is largely set forth in this disclosureand figures as part of a cassette 14 for an infusion pump, the flow stopdevice should not be view as limited to implementation in such acassette arrangement. In other embodiments, for example, the flow stopmay be readily implemented in a pressure plate design for an infusionpump that is used as part of an administration set that is configuredfor use with an IV bag or other fluid source.

FIG. 2 illustrates an exploded view of an infusion pump, with thecontrol module 12 and cassette 14 in a separated arrangement. Moreparticularly, the control module 12 and cassette are depicted asindependently tilted such that the components on the lower surface ofthe control module 12 and components on the upper surface of thepressure plate 18 are shown. A flow stop assembly 20, tubing 22, and amedication bag 24 are represented in this figure as well. In theembodiment shown, the flow stop assembly 20 includes an occlusion arch28 and a flow stop arm 30.

The lower surface of the control module 12 includes hinge pins 32 and alatching mechanism 34 in a recess 35 that join the control module 12 andcassette 14 when the components are coupled together. The control module12 further includes an inlet valve 36, an outlet valve 38 and acentrally located expulsor 40. Also, seen in FIG. 2 are an upstreamocclusion sensor 42, a downstream occlusion sensor 44, an air detectorsensor 46 and a plurality of cassette detection pins 48.

The pressure plate 18 shown in FIG. 2 includes a top and bottom surface,two side walls 52 as well as an upstream wall 54 and a downstream wall56. The cassette 14 includes a source of fluid contained within a bag 24or a syringe (not shown). The bag 24 or other fluid reservoir may alsobe positioned remote from the control module 12 and pressure plate 14.Pressure plate 18 includes a plurality of guides 62 positioned on thetop of pressure plate 18 which keep tube 22 in place on pressure plate18. Located intermediate at least one pair of guides 62 is a rampplatform 63 for providing the correct height to a passing tube 22.Pressure plate 18 also includes a rail 64 and various supportingstructures 65 which surround pressure plate 18.

As shown in the figures, pressure plate 18 attaches to the controlmodule 12 with hooks 66 and loop 68. In particular, hooks 66 engage pins32 of the control module 12, and loop 68 is received within recess 35.Recess 35 includes a latch 34 which selectively engages loop 68 to lockpressure plate 18 to the control module 12. When pressure plate 18 islocked to control module 12, tube 22 is continually engaged by at leastone of valves and expulsor features 36, 38, and 40 such that the tube 22is constantly occluded. When in operation, the valves and expulsorselectively squeeze tube 22 against pressure plate 18 to effect themovement of fluid through tube 22.

Also shown in FIG. 2 is flow stop assembly 20, made up of flow stopocclusion arch 28 and flow stop arm 30. Although not shown assembledinto the pressure plate 18 in FIG. 2, the flow stop assembly 20 can beunderstood as being adapted for assembly into the pressure plate 18between the loop 68 and the central tubing support surface 70. Theocclusion arch 28 is attachable to the pressure plate as it is adaptedwith snaps to secure into the features of the rail 64 and/or supportstructures 65 surrounding the center of the base plate 18.

Located adjacent the occlusion arch 28 is a recessed area 74 andfeatures that allow for integration of a flow stop assembly 20. The flowstop arm 30 is spring biased via spring 78 and generally extendspartially across the opening provided by the occlusion arch 28. Thepurpose of the integrated flow stop assembly 20 is to reduce the risk ofmedication free flow. In general, the flow stop assembly 20 is able toaccomplish this by spring-biased pressure contact of the flow stop arm30 against the tubing 22 passing through the occlusion arch 28. In otherwords, the flow stop arm 30 is biased such that the opening of theocclusion arch 28 is reduced so that the tubing passing through isinterfered with and occluded. This will be shown and described ingreater detail in connection with the subsequent figures of theapplication.

FIG. 3 is an exploded view of an embodiment of a flow stop assembly 20.The assembly allows for selectively occluding the tubing of an infusionpump and includes a flow stop occlusion arch 28 and a flow stop arm 30.

The flow stop occlusion arch 28 is a multi-directional, elongatestructure having a first end 102 and a second end 104. The first end 102shown in FIGS. 3 and 4 has a tab retention feature 106 for coupling tothe raised rail 64 or corresponding supporting structures of thepressure plate 18. The second end 104 has tab structures 108 enablingthe occlusion arch to clip beneath or within retention features found onthe raised rail 64 or adjacent supporting structures. Defined betweenthe first and second ends 102 and 104 of the occlusion arch 28 is anaperture 110. This aperture 110 is shaped to surround an insertedinfusion tube 22, for an infusion pump, that may be threadedtherethrough when in use. The arch 28 has both an upwardly projectingportion 112 that forms a portion of the aperture 110 as well as anoutwardly projecting portion 114 that forms a surrounding portion of theaperture 110 as well. The flow stop occlusion arch 28 is particularlyadvantageous as it is independently attachable and may remain detachedfrom the pump for an initial portion of time when assembling thecassette, including when one is situating the tubing 22.

The flow stop arm 30 is a multi-directional body having a push tab 120at one end and a pivoting pin 122 at the other end. The intermediatebody portion 124 of the arm 30 is narrow in its width and extends in amulti-tiered fashion. The push tab 120 generally has a small flat topsurface 126 of converging shape. The bottom of the push tab 120 includesa conical protrusion 128 axially receivable within a spring member 78.Accordingly, a user can press vertically downward against the topsurface 126 of the push tab 120 against the bias of the spring 78 todisplace the flow stop arm when in operation. As depicted in FIG. 3, thepivoting pins 122 extend horizontally from the sides of the flow stoparm 30 at the opposite end of the arm from the push tab 120. The pins122 are shaped for placement and pivotal coupling in the concave arcuatesurfaces 130 near the second end 104 of the occlusion arch 28. Further,when assembled, the body portion 124 of the arm 30 is placed through theaperture 110 formed by the arch 28. This arrangement causes the topsurface 130 of the body of the arm to define the lower opening of apassageway through the aperture 110 of the occlusion arch 28.Accordingly, depression of the flow stop arm 30 will provide a greateropening through which an infusion tube 22 can pass. Release of the arm30 will result in an upward movement of the arm 30 and upper surface 130to provide a smaller passageway for an inserted infusion tube and willaccordingly result in occlusion of the tube when the arm 30 is not beingdepressed. This arrangement is illustrated more fully in the assembledview of the flow stop assembly in FIG. 4.

FIG. 5A illustrates generally an alternate assembled view of anembodiment of flow stop assembly 20 coupled together in an assembledfashion. In this embodiment the first end of the occlusion arch 28 hasalternate tabs 136 for snapping into the pressure plate rail 64 andsupporting structures.

FIG. 5B illustrates the flow stop assembly of FIG. 5A inserted into apressure plate 18. In general, the flow stop assembly extendshorizontally across the pressure plate 18 of the pump from the front ofthe pump to the back of the pump with one end located proximate the rail64 on side 150 and the other end of the assembly proximate the rail 64and supporting structures on the other side 152. Further, the flow stopassembly 20 generally rests within a vertically recessed slot 74 withinthe pressure plate 18. The recess 74 traverses the pump from front side150 to back side 152 and is located between the between the loop 68 andthe central tubing support surface 70.

FIG. 6 is a cross-sectional view of the recess 74 of the pressure plate18 in which the flow stop assembly 20 is placed during manufacture andassembly of the cassette 14 or pressure plate 18. Unlike some prior artdesigns, the recess 74 does not include ramp-like features at the edgesof the pressure plate surface at locations 170 and 172, for example. Byeliminating ramp-like features at these locations, the new flow stopassembly 20 does not suffer from potential unwanted back pressureeffects that can impact the accuracy and desired operation of aninfusion pump 10.

FIG. 7A illustrates generally a pressure plate 200 of the prior art.FIG. 7B illustrates generally a top view of an assembled pressure plate200, infusion tubing 202 and a flow stop arm 204 of the prior art. Thesefigures illustrate a prior art arrangement in which an occlusion arch206 was integrally formed with the pressure plate 200. Assembling thisdesign during manufacturing is somewhat challenging. For example, inorder to assemble tubing into the configuration shown in FIG. 7B, it isnecessary to thread tubing through the very narrow opening in the archcreated by the spring biased flow stop arm 204. Alternatively, allowingone to thread this structure through an attachable arrangement, likethat of embodiments of the present invention, greatly reducesmanufacturing difficulties and substantially reduces assembly costs.

FIG. 8 is an exploded view of an alternate embodiment of a flow stopassembly, with a flow stop occlusion arch 328 and flow stop arm 330. Theocclusion arch 328 is a structural clip having a first end 332 and asecond end 334.

Each of these ends has a pair of legs 335 equipped with tab retentionfeatures 336 for coupling to the raised rail or corresponding supportingstructures of the pressure plate 18. The tab retention features 336 mayclip beneath or within retention features found on the raised rail oradjacent supporting structures of the pressure plate 18. Located betweenthe first and second ends 332 and 334 of the occlusion arch 328 is anaperture 340. This aperture 340 is shaped to surround an insertedinfusion tube 22, for an infusion pump, that may be threadedtherethrough when in use. The arch 328 has both an upwardly projectingportion 342 that forms a portion of the aperture 340 as well as anoutwardly projecting portion 344 that forms a surrounding portion of theaperture 340 as well. The flow stop occlusion arch 328 is particularlyadvantageous as it is attachable and may initially remain detached fromthe pump when assembling the cassette, including situating the tubing22.

The flow stop arm 330 is a multi-directional body having a push tab 350at one end and a pivoting pin 352 at the other end. The intermediatebody portion 354 of the arm 330 is narrow in its width and extends in amulti-tiered fashion. The push tab 350 generally has a small flat topsurface 356 of converging shape. The bottom of the push tab 350 includesa conical protrusion 358 axially receivable within a spring member 78.Accordingly, a user can press vertically downward against the topsurface 356 of the push tab 350 against the bias of the spring 78 todisplace the flow stop arm when in operation. The pivoting pins 352extend horizontally from the sides of the flow stop arm 330 at theopposite end of the arm from the push tab 350. The pins 352 are shapedfor placement and pivotal coupling near the second end 334 of theocclusion arch 328. Further, when assembled, the body portion 354 of thearm 30 is placed through the aperture 340 formed by the arch 342. Thisarrangement causes the top surface 360 of the body of the arm 330 todefine the lower opening of a passageway through the aperture 340 of theocclusion arch 328. Accordingly, depression of the flow stop arm 330will provide a greater opening through which an infusion tube 22 canpass. Release of the arm 330 will result in an upward movement of thearm 330 and upper surface 360 to provide a smaller passageway for aninserted infusion tube and will accordingly result in occlusion of thetube when the arm 330 is not being depressed.

FIG. 9 depicts an alternate embodiment of a flow stop arch design. Thisembodiment depicts an alternate attachable flow stop arch component,occlusion arch 400, as well as retaining features 410 and 420 that wouldbe integrated into the pressure plate 18 of such a design. The occlusionarch 400 is a structural clip having a first end 422 and a second end424.

The first end 422 is equipped with a tab retention feature 426 forcoupling to the recessed structure 410 of the pressure plate 18. The tabretention features 426 may clip beneath or within this recessedstructure 410. The second end 424 includes a protrusion 428 that extendsslightly in a horizontally disposed direction. This protrusion 428 maybe aligned to fit within a retaining feature 420. A raised arch portion430 comprises the central body of the occlusion arch 400 between thefirst and second ends 422 and 424. This raised arch portion 430partially defines an aperture in its interior. When the occlusion arch400 is inserted into the respective retaining features 410 and 420 thearch perimeter combines with the pressure plate to form an aperture intowhich an infusion tube 22 may be inserted and threaded therethrough. Theocclusion arch could be used together with a flow stop arm in someembodiments. In other embodiments the occlusion arch operates on its ownto sufficiently compress a infusion tube for occlusion.

FIG. 10 depicts an alternate embodiment of a flow stop arch design. Thisembodiment is largely the same as the one depicted in FIG. 9, but has aslightly different retaining feature 520 from the retaining feature 420shown in FIG. 9. Specifically, the retaining feature allows access fromtwo sides. Accordingly, the ability to insert the protrusion 528 at theend 524 of the flow stop arch component 500 from multiple directions isenabled.

Certain embodiments may further include a sensor as part of the infusionpump that could detect the presence of the flow stop feature. This couldbe another sensor beyond the cassette detection pins 48 or could utilizeone of the pins 48. Accordingly, the pump 12 would alarm if it did notdetect the flow stop feature. This would also be beneficial insituations where the plate or housing became detached from the pump 12,since the pump would sound an alarm.

The cassette for an infusion pump may be assembled by first providing aninfusion pump reservoir cassette containing an interior reservoir bagand a top surface comprising a pressure plate. This method furtherincludes extending an infusion tubing, coupled to the reservoir bag at alocation proximate an opening in the pressure plate, through an aperturein an attachable flow stop assembly and across the surface of thepressure plate. The attachable flow stop includes an attachableocclusion arch and an attachable flow stop arm. The attachable flow stopdefines the aperture, and has legs with one or more tab members forproviding coupled engagement and an attachable flow stop arm. The methodfurther includes securing the tab members to features in the pressureplate.

It should also be appreciated that the exemplary embodiment or exemplaryembodiments are only examples, and are not intended to limit the scope,applicability, or configuration of the invention in any way. Rather, theforegoing detailed description will provide those skilled in the artwith an enabling disclosure for implementing the exemplary embodiment orexemplary embodiments. It should be understood that various changes canbe made in the function and arrangement of elements without departingfrom the scope of the invention as set forth in the appended claims andthe legal equivalents thereof

The embodiments above are intended to be illustrative and not limiting.Additional embodiments are within the claims. Although the presentinvention has been described with reference to particular embodiments,workers skilled in the art will recognize that changes may be made inform and detail without departing from the spirit and scope of theinvention.

Various modifications to the invention may be apparent to one of skillin the art upon reading this disclosure. For example, persons ofordinary skill in the relevant art will recognize that the variousfeatures described for the different embodiments of the invention can besuitably combined, un-combined, and re-combined with other features,alone, or in different combinations, within the spirit of the invention.Likewise, the various features described above should all be regarded asexample embodiments, rather than limitations to the scope or spirit ofthe invention. Therefore, the above is not contemplated to limit thescope of the present invention.

For purposes of interpreting the claims for the present invention, it isexpressly intended that the provisions of Section 112, sixth paragraphof 35 U.S.C. are not to be invoked unless the specific terms “means for”or “step for” are recited in a claim.

1-14. (canceled)
 15. A method of assembling a cassette for an infusionpump, comprising: providing an infusion pump reservoir cassettecontaining an interior reservoir bag and a top surface comprising apressure plate; extending an infusion tubing, coupled to the reservoirbag at a location proximate an opening in the pressure plate, through anaperture in an attachable flow stop assembly and across the surface ofthe pressure plate, the attachable flow stop, including: an attachableocclusion arch defining the aperture and having legs with one or moretab members for providing coupled engagement; an attachable flow stoparm; and securing the tab members to features in the pressure plate. 16.The method of claim 15, wherein the attachable occlusion arch includesfour legs each having as least one tab member.
 17. The method of claim15, wherein the attachable occlusion arch includes three tab members.18. The method of claim 15, wherein the attachable occlusion archentirely defines aperture passageway.
 19. The method of claim 15,wherein the attachable occlusion arch partially defines aperturepassageway.